Various types of privacy screens are known in the prior art. Most screens are ii built in, with screen dimensions having to be met during building construction, or existing screen offerings must be custom built to accommodate various structures to which the screens are fitted. Additionally existing screens are not typically equipped with corners. What has been needed is a modularly constructible screen system that provides screen panels on tracks such that screen panels may be optionally opened or closed as might windows be. Further, a screen system is needed that provides corner post, center posts and end posts wherein the modularity is continued as desired. Such a system must be easily assembled even by a novice, and even offer the capability of being cut to fit by the novice. The present system provides these advantages.